Business Segments (Details) $ in Thousands		3 Months Ended	12 Months Ended
	Oct. 29, 2018 segment	Sep. 30, 2021 USD ($) segment	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	3	2	2
Segment Reporting Information [Line Items]
Revenue			$ 1,464,429	$ 1,429,456	$ 1,444,441
Sales to external customers			1,464,429	1,429,456	1,444,441
Earnings before interest, taxes, depreciation and amortization (EBITDA)			99,317	168,448	59,672
Depreciation and amortization			113,664	107,268	98,236
Interest expense			(37,575)	(46,682)	(58,556)
Income before income taxes			61,742	121,766	1,116
Income tax expense			(10,080)	(7,371)	(9,587)
Net income (loss)			51,662	114,395	(8,471)
Capital expenditures			75,293	88,456	88,869
Assets		$ 1,868,891	1,868,891	1,844,458
Goodwill		407,376	407,376	397,205	392,890
Integrated Solutions and Services
Segment Reporting Information [Line Items]
Sales to external customers			959,886	944,182	910,834
Capital expenditures			60,407	75,551	73,656
Goodwill					222,013
Applied Product Technologies
Segment Reporting Information [Line Items]
Sales to external customers			504,543	485,274	533,607
Capital expenditures			6,955	6,237	7,589
Goodwill					170,877
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue			1,568,932	1,514,177	1,551,317
Operating Segments [Member] | Integrated Solutions and Services
Segment Reporting Information [Line Items]
Revenue			980,852	954,542	919,985
Sales to external customers			959,886		910,834
Earnings before interest, taxes, depreciation and amortization (EBITDA)			147,251	145,655	148,593
Depreciation and amortization			70,585	67,489	57,217
Assets		887,265	887,265	835,307
Goodwill		233,830	233,830	224,381
Operating Segments [Member] | Applied Product Technologies
Segment Reporting Information [Line Items]
Revenue			588,080	559,635	631,332
Sales to external customers			504,543		533,607
Earnings before interest, taxes, depreciation and amortization (EBITDA)			82,891	134,258	69,377
Depreciation and amortization			14,423	14,226	17,675
Assets		656,362	656,362	598,701
Goodwill		173,546	173,546	172,824
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales to external customers			104,503	84,721	106,876
Intersegment Eliminations [Member] | Integrated Solutions and Services
Segment Reporting Information [Line Items]
Sales to external customers			20,966	10,360	9,151
Intersegment Eliminations [Member] | Applied Product Technologies
Segment Reporting Information [Line Items]
Sales to external customers			83,537	74,361	97,725
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Earnings before interest, taxes, depreciation and amortization (EBITDA)			(130,825)	(111,465)	(158,298)
Depreciation and amortization			28,656	25,553	23,344
Capital expenditures			7,931	6,668	$ 7,624
Assets		$ 325,264	$ 325,264	$ 410,450